Attention-Deficit/Hyperactivity (ADHD) is a developmental disorder characterized by age-inappropriate levels of restlessness, impulsivity, and/or inattention that is increasingly diagnosed and treated among adolescents. Research performed in our lab has demonstrated that normal adolescents are at heightened risk for insufficient sleep and are likely to display behavioral and academic problems due to sleep restriction. Among adolescents predisposed to behavioral and academic difficulties, such as those with ADHD, the impact of shortened sleep may be amplified. Characteristics of ADHD may increase both the risk for and vulnerability to restricted sleep. In addition, restricted sleep may affect attitudes toward treatment, particularly since psychostimulant medication is a common treatment for ADHD and also an effective countermeasure for the effects of restricted sleep. The Exploratory/Developmental Grant (R21) Program was selected because the proposed project involves "research directions requiring preliminary testing and development" and uses "approaches new to a substantive area". The projects applies techniques and expertise developed describing sleep in normal adolescents to the exploration of sleep patterns and the response to restricted sleep among adolescents with ADHD. Study 1 confirms the validity of the actigraphy algorithm derived in non-ADHD samples for measuring sleep/wake states in ADHD adolescents, using laboratory-based nocturnal polysomography as the research standard. Actigraphy is then used to assist in describing self-selected sleep patterns and verifying compliance with assigned sleep schedules in Study 2. Study 2 uses a 3-phrase protocol to explore sleep- patterns, daytime sleepiness, ADHD symptoms, perceived need for medication, and medication use under self-selected, extended, and restricted sleep conditions. We hypothesize that self-selected sleep of adolescents with ADHD will be shortened on school nights. Further, under conditions of restricted sleep, we predict that adolescents with ADHD will show increased sleepiness, increased ADHD symptom severity, and increased perceived need for psychostimulant medication.